Schizophrenia, Recreational Cannabis Use, and Medical Marijuana

August 31, 2023

Blog, Child Psychiatrist, Parenting, Parenting decision making, Psychopharmacology

By Kentlands Psychotherapy Intern

Schizophrenia is a disorder that affects a person’s ability to think, feel, and behave. The two main symptoms are delusions and hallucinations. The exact cause of schizophrenia is unknown. However, there are emerging studies that show that marijuana use could be one potential risk factor for schizophrenia, especially in young men.

This could have to do with the fact that marijuana use is becoming increasingly popular and has also gotten more potent since the 1970s. A 2020 study from the University of Bath found that THC concentrations have increased by about 2.9 milligrams each year since the 1970s. The study also found that as the potency of marijuana increased, marijuana-associated psychosis rose as well.

According to the NIH, cannabis intoxication can cause a temporary psychotic episode in some people. Cannabis-induced psychosis is when marijuana use causes acute symptoms of psychosis such as paranoia, delusions, and, in rarer cases, hallucinations. Cannabis-induced psychosis is rare, but when it does occur, it can be serious. The majority of cases are temporary. However, experiencing this psychotic episode could be linked with a risk of later developing a chronic psychotic disorder, even after discontinuation of marijuana use.

A study published in Psychological Medicine explored this connection. They found evidence of an association between schizophrenia and cannabis use disorder in men and women, with a much stronger association in young men. The researchers of the study proposed that an estimated 30% of schizophrenia cases in men aged 21-30 could have been prevented by avoiding marijuana.

On the other hand, critics may argue that these studies may just show a correlation rather than showing that the use of marijuana directly contributes to schizophrenia. It may just be that people with schizophrenia are more likely to be marijuana users. However, people with many types of mental illness are at a greater risk for using illicit substances, not just schizophrenia. People with psychosis could also be using marijuana in an attempt to self-medicate, sending them into an unhealthy spiral.

There is growing research that medical marijuana could be helpful in easing the symptoms of certain conditions, especially in pain relief. However, this could be a similar situation to how “big pharma” marketed the prescribing of opioids and Oxycontin for pain, all while misrepresenting and hiding the risks that opioids present. Purdue Pharma, one of the main opioid manufacturers, promoted Oxycontin as less addictive than it is and was a factor in the first wave of casualties related to the use of prescription opioids. Purdue Pharma has since pleaded guilty to criminal charges in relation to its deceitful marketing of the addictive painkiller.

While the current interest in the potential benefits of medical marijuana is not equivalent to Purdue Pharma misrepresenting the risk to pain patients using Oxycontin, we are still learning about the risk-benefit profile of medical marijuana. Marijuana enthusiasts want to see the drug destigmatized, which could be another factor in the current promotion of medical marijuana that is not necessarily in the best interest of public health. In a 2021 article published by PubMed, cannabis was described as a “miracle drug”, but with multiple sources showing a link between cannabis use and psychosis, describing it as a “miracle” may be misleading if not dangerous. The journal Medical Cannabis and Cannabinoids, from which this article appeared, may have a pro-marijuana bias through possible financial ties to the medical marijuana industry. The journal is affiliated with The Alliance for Cannabinoid Medicines, whose website claims to “advance knowledge” on medical marijuana. However, the IACM website offers a paid membership as an associate, which is described as “for everybody supporting the medical use of cannabis and cannabinoids”. It was also not possible to identify the funding source for the journal.

Furthermore, medical marijuana has its benefits and risks, just like any other drug. It is not a “miracle”. Even when someone is legally prescribed medical marijuana, it does not diminish the risks that marijuana use can present. More research is needed, and because marijuana enthusiasts are often the ones conducting this research, we need to acknowledge potential bias.

It is also important to keep in mind that those treated with medical marijuana are in a clinical setting, with the supervision and approval of a doctor. This is much different than smoking “weed” on your own without a doctor’s supervision, with marijuana that is often purchased from illegal drug dealers and could potentially be laced with other substances.

It is clear that if a person already suffers from schizophrenia, marijuana use can make their symptoms worse. Furthermore, schizophrenia runs in families- those who have a parent or sibling with the condition have a higher chance of also being diagnosed with the illness. Cannabis use can make their odds worse, from one in ten to just one in five.

Carsten Hjorthøj, the lead author of the Psychological Medicine study, says that “Increases in the legalization of cannabis over the past few decades have made it one of the most frequently used psychoactive substances in the world, while also decreasing the public’s perception of its harm. This study adds to our growing understanding that cannabis use is not harmless and that risks are not fixed at one point in time”.